17 April 2012

Studying Earth Craters For Clues on Life On Mars

Earth, Mars, and the Moon

Earth is bigger than Mars. Earth is about two times the diameter of Mars. Nearly 70% of Earth is covered with liquid water; Mars has none. Although Mars may have had liquid water at one time in its early years.

Despite the differences, Mars is similar to Earth than any other planet in the solar systems. Mars, like Earth, has valleys and mountains, weather and seasons, and volcanoes and ice caps. At 24 hours and 39 minutes, the Martian day is only a little bit longer than Earth's. Because of these similarities, studying some geographical features in Earth helps scientists know more about Mars.

Asteroid craters on Earth give clues in search for life on Mars

Craters made by asteroid impacts may be the best place to look for signs of life on other planets, a study suggests.

Tiny organisms have been discovered thriving deep underneath a site in the US where an asteroid crashed some 35 million years ago.

Scientists believe that the organisms are evidence that such craters provide refuge for microbes, sheltering them from the effects of the changing seasons and events such as global warming or ice ages.

The study suggests that crater sites on Mars may also be hiding life, and that drilling beneath them could lead to evidence of similar life forms.
Video: Earth and Mars Craters

Researchers from the University of Edinburgh drilled almost 2km below one of the largest asteroid impact craters on Earth, in Chesapeake, US. The Chesapeake Bay impact crater was formed by a bolide (a generic large crater-forming projectile) that hit the eastern shore of North America about 35 million years ago, in the late Eocene epoch. It is one of the best-preserved marine impact craters, and the largest known impact crater in the U.S. The continuous movement of sediments over the rubble of the crater has helped shape Chesapeake Bay.

Samples from below ground showed that microbes are unevenly spread throughout the rock, suggesting that the environment is continuing to settle 35 million years after impact.

Scientists say that heat from the impact of an asteroid collision would kill everything at the surface, but fractures to rocks deep below would enable water and nutrients to flow in and support life. Some organisms grow by absorbing elements such as iron from rock.

Professor Charles Cockell, of the University of Edinburgh's School of Physics and Astronomy, said: "The deeply fractured areas around impact craters can provide a safe haven in which microbes can flourish for long periods of time. Our findings suggest that the subsurface of craters on Mars might be a promising place to search for evidence of life."